An Unlikely Alliance
by kawaiicrississi
Summary: Dean is back on an old case that he thought had gone cold. What happens when it leads him to a small town called Beacon Hills, and an old friend isn't who he thought she was?
1. Chapter 1

The rain fell heavily, drumming against the roof of the vehicle. He was driving down an open road, letting his headlights blaze his path. He was speeding but he wasn't concerned about it, if the police pulled him over they would be giving a ticket to someone who didn't even exist.

Normally, his favorite cassette would be at a much louder volume but for once he had it at a respectable level, a dull hum, merely background noise so it didn't get too quiet. He had no one to talk to at the moment considering the car's only other occupant was asleep in the passenger seat.

So, he settled for humming along and lightly drumming his fingers on the steering wheel, sometimes in time with the song and other times with the rain. He flinched when muffled ringing came from the glovebox. He carefully reached over and opened it, trying to find out which cell phone was actually the one making all the racket while silently praying his passenger stayed asleep.

He finally managed to discover which offending piece of technology was causing him so much trouble and frowned. He knew this number, but never expected a call. He flipped the phone open, addressing the caller by name, not hiding his surprise.

The familiar voice on the other end was confirmation. It made him listen and listen carefully.

"Alright, alright. Calm down." He murmured gently, given he had a soft spot for the person he was talking to. "We're a few hours out." He listened again for a moment. "You did the right thing. Just sit tight and let us deal with it." Out of the corner of his eye, he noticed his companion had stirred, and was now looking at him expectantly and curiously. "Ok. See you soon Sweetheart. Bye."

"We got a job?" His passenger asked, already knowing the answer to his question but finding it best to ask anyway.

"Yeah, we got a job." He answered, pushing the accelerator down even farther, sending the car roaring through the downpour.


	2. Chapter 2

~Earlier that day~

A normal morning.

That's how her day started.

Just a usual morning spent with four boys that she had come to call her family. Some of her best friends in the entire world. So how did it end up as one of the most stressful days of her life?

Their morning was as uneventful as ever. She was the first one up after a wild pack bonding the night before which was spent seeing who could stay up the longest while watching movies and eating pizza on the floor of Derek's loft. It was initially supposed to be a boy's night, but they couldn't exactly leave her out since she lived there.

Stiles had groaned and grumbled half-heartedly but in the end, he really didn't mind. Scott would never turn anyone away, even for something that small. And Liam, of course, was immediately on her side. He had perked up significantly when she had walked into the room. That boy was like her human puppy. It didn't help that she treated him like one and called him Baby Wolf, but that was their relationship. Wherever she was, Liam was usually found right on her heels. He looked up to her and she enjoyed his company.

The first thing she did was try and clean up a bit and soon enough Derek joined her. They didn't talk much. They didn't need to. They just enjoyed each other's company as they made breakfast for themselves and the other three boys, who she had yet to awaken since they were known for loving their sleep.

Eventually the aroma of breakfast managed to stir them and convince them to get up and face the day. Scott, Stiles, and Liam groggily stumbled into the kitchen as she and Derek dished out breakfast. When they were done eating, they got dressed and went grocery shopping, the boys somehow managing to talk Derek, who's probably the most stubborn person on the planet, into buying all kinds of snacks and junk food. Nothing out of the ordinary.

When they got back, they decided to make lunch.

So, they started an assembly line. Derek was first, picking out kinds of bread and setting them on a plate before passing it to Stiles who was in charge of spreads: jellies, jams, peanut butter, mustard, mayo, etc. Then the plate got sent to her where she had lunch meat, lettuce, and cheeses. She then smushed the two halves together and slid it over to Scott who had a large knife in his hand that he was using to cut the crusts off their sandwiches before shuttling the plate to Liam who was dumping different kinds of chips on it, putting more on the floor and countertop than the actual plate.

That's where the normality ended.

As she passed Scott the last plate, he suddenly went very still, the knife hovering over the sandwich as if he wasn't sure if he wanted to cut it or not.

"Scott?" She asked quietly. He didn't look at her, didn't move. "Scott? Are you alright?" She asked again, gaining the attention of the other three boys. She reached out to him, putting her hand on his shoulder.

She really wished she hadn't.

Scott whirled toward her, backhanding her across the face incredibly hard. Impossibly hard, even with his alpha strength. She spun into Stiles, knocking them both to the ground.

Derek and Liam moved toward Scott but something in his eyes made her scream, "Don't! Stay away from him!" As she tried desperately to untangle her legs from Stiles'.

But her warning was heard too late.

Scott, smiling wickedly, slashed downward with the knife, biting a deep, long gash across Liam's chest.

"NO!" She wailed as Liam collapsed to the ground, letting out a strangled grunt.

Scott turned back toward her, Stiles, and Derek, confirming her suspicions.

His eyes were completely black.

"Scott what the hell is wrong with you?" Stiles demanded, jumping up and looking like he wanted to grab Scott, shake some sense into him, before running to Liam who was lying motionless, but was still wary of the wicked sharp knife in Scott's hand that was dripping with Liam's blood.

"That's not Scott." She warned through clenched teeth, trying not to hiss in pain as she picked herself up off the ground.

A twisted smile crept onto Scott's face as he twirled the knife effortlessly in his hand.

"Who are you?" She asked, motioning for Stiles and Derek to stay where they were. She didn't want them to try anything. Scott was incredibly dangerous at the moment, especially with that knife in his hand.

"You don't remember?" Scott responded in mock disbelief, placing a hand on his chest as if he was wounded. "I'm hurt."

"You're obviously not worth remembering." She snarled, keeping her attention split between Scott and the knife.

Scott tsked, shaking his head in disappointment. "Maybe this will help jog your memory." He raised the knife, getting ready to plunge it into his own chest.

She moved forward before she even knew what she was doing, grabbing his wrist and twisting until the knife clattered to the floor. She winced slightly as Scott's wrist cracked but a fractured wrist would heal, his heart with a knife through it would not. She managed to wrestle him to the ground and pinned him, motioning to Stiles and Derek to help her hold him down.

Scott cackled. "Thanks for the fun, but I should be going now. I'll see you later."

His mouth opened in a scream, thick, foul-smelling black smoke pouring out and sinking through the floor. Scott went limp under them. Stiles and Derek moved to get off but she stopped them.

"Not yet." She said quietly. "We have to make sure he's really back."

Scott stirred, groaning as he did so. "Ow my head." He muttered. When he finally noticed there was a weight on his back he twisted to look up at her, his eyes going wide with worry and guilt. "That wasn't a dream was it?" He asked.

"No, it wasn't." She answered gently before swiftly standing and moving to where Liam still lay, wheezing heavily. She knelt down beside him and moved his ripped shirt slightly so she could get a better look at his wound. "Someone get the first aid kit." She called, ripping Liam's shirt open and gently slapping his cheeks, trying to rouse him.

Scott moved slowly to her side with wide eyes as he looked at what he had done to his beta.

"Scott," She started, about to suggest that he not look, when Stiles came back with the first aid kit.

He handed it to her and he and Derek knelt down.

"What can we do?" Derek asked in a small voice that managed to surprise her since it was so unlike him.

She was about to answer when a rattling sound came from the ceiling. "We'll have to patch him up, just not here." She whispered, glancing upward expecting the black smoke to come back at any moment.

"Are you going to tell us what the hell happened and why I tried to kill my beta?" Scott asked, terrified tears swimming in his eyes.

"Not here." She repeated. "Stiles, Derek, go to the garage and grab the bag of road salt and bring it to my room. Scott, you're gonna help me get Liam there." She grabbed one of Liam's arms and slung it over her shoulder. Scott did the same on his other side.

"What's with the salt?" Derek wondered.

"Just trust me, we need it." They nodded and moved to walk away but she called them back with one last piece of advice. "Look, stay together, don't take your eyes off of each other for even a second, do you understand?" She finally let them go when she got their nods of confirmation.

She and Scott had a bit of a hard time dragging Liam up the stairs, seeing as he was still unconscious, but they needed to barricade themselves and the bedrooms on the second floor were the only rooms that had only one entrance. They laid Liam on the bed as gently as they could and opened the first aid kit just as Stiles and Derek rejoined them.

"One of you line the entire room with salt, the other come help me." She ordered.

Neither of them questioned it as Stiles grabbed the bag and began pouring it around the perimeter of the room. Derek joined her and Scott next to the bed.

She uncapped a bottle of clear liquid and paused, looking at Derek and Scott. "You're gonna need to hold him down."

"Why?" Scott asked, looking at the bottle she held with worried eyes, but he was already grabbing Liam's arms as Derek laid across his legs.

"This is gonna hurt." She warned. "But it'll also help trigger the healing process." She took a deep breath. "Sorry Liam." She upturned the bottle, pouring it over his wound.

Liam immediately became livid, screaming and trying to buck Scott and Derek off as he tried to escape the burning pain spreading throughout his chest, his eyes flashing yellow.

She tossed the now empty bottle of rubbing alcohol onto the floor and gripped Liam's shoulders, using all of her weight to keep him pinned to the bed. "I'm sorry. I'm sorry. It's almost over Liam. I'm sorry." She muttered uselessly to him.

Liam finally stopped convulsing and lay panting on her bed.

"Ok," She said, slowly taking her hands off his shoulders. "Ok guys let him up."

Liam's gaze was flicking frantically between all of their faces, his eyes back to blue but filled with pain. They landed on Scott and he started to hyperventilate trying to shuffle away from him.

She put her hands out to stop him. "Liam. It's ok. He's ok now."

Liam ignored her, attempting to sit up and gasping in pain as he pushed himself as far from Scott as he could get before passing out again.

Scott kept his eyes on the ground, his body language screaming hurt and guilt.

She sighed and rummaged through the first aid kit until she found some butterfly bandages and gauze. "The cut should start healing on its own now but we still need to clean and cover it." She muttered to no one in particular. "He should be ok in time."

Scott's eyes met hers and he immediately knew what she meant. Liam wouldn't blame him once he knew the whole story.

"So, what was that black smoke?" Stiles asked timidly, wondering if it was the right time to bring it up.

"A demon." She answered, getting straight to the point.

"And the salt?"

"It's like their Mountain Ash. They can't cross it."

"Why did it possess Scott and make him try and kill Liam?" Derek asked.

"Demons know things about people." She explained as she carefully cleaned the dried blood off Liam's chest with a wet rag. "Their deepest, darkest fears. They manipulate them and then feed off the fear they cause. Liam's biggest fear was obviously that Scott would hurt him."

Scott winced and any further questions were dropped.

Derek and Stiles wandered around the room, Derek pacing aimlessly while Stiles double checked the salt barrier he had laid. Scott stayed next to the bed and held Liam's limp hand in his.

She glanced up at him as she discarded the now bloody rag. "I'm sorry about your wrist."

Scott shrugged, not taking his eyes off of Liam's face. "You did what you had to do. Besides, it healed already."

She shook her head as she placed butterfly bandages over the deepest sections of the long cut. "I probably could've disarmed you without fracturing your wrist." She admitted.

Scott sighed heavily. "I was still aware of everything. I could see what he was doing." Scott suddenly looked exhausted, dark rings forming under his eyes, his skin pale and chalky. He shook his head, trying to rid himself of the memory of his beta falling to the floor. "How do you know all this stuff about demons anyway?" He asked, changing the subject.

She hesitated, not knowing how much to give away at this time. "I've come across them before." She finally admitted.

"Specifically the one that possessed me?" Scott wondered.

She nodded slowly as she taped down large gauze pads to Liam's chest. "Yeah." She whispered. "I've run into him before." She didn't give Scott the opportunity to ask any more questions. "I'm sorry but that's all you're getting for now." She said with a weak smile.

Scott nodded in understanding and dropped the subject.

"That should do it." She finally said after wrapping Liam's torso with gauze to keep any more bleeding contained as much as possible. "He should be fine fairly soon. I have to make a phone call. It'll only take a minute." She quickly wiped off as much of Liam's blood off her hands as she could and grabbed her cell from the nightstand where she had put it when she was patching Liam up, dialing a number she never thought she would have to use again.

She listened to it ring. Two…three…four times now. She chewed her bottom lip as it rang a fifth time and she almost hung up but finally he answered.

" _Skylar?"_

"Dean, I need your help."


	3. Chapter 3

**So, in case you haven't guessed it yet, Skylar is my OC from the Teen Wolf universe. :) She is also featured in my other Teen Wolf story Introductions. Thanks for the reads and favorites and follows, it all means so much to me. Anyway, without further ado, back to the story. :)**

A knock on the bedroom door startled everyone in the room. Skylar motioned for them to stay quiet and moved noiselessly over to the door.

"Derek? Skylar?" A familiar voice called, sounding very confused and worried. "Are you guys in there?"

"Audrey?" Skylar called back, still not believing enough to open the door just yet.

"Yeah. Is everything alright? Isaac and I just got back and we saw the blood in the kitchen…" Audrey trailed off, waiting for an explanation and for the door to be unlocked and opened.

Skylar cursed under her breath. In all the panic-inducing events that had taken place, she had forgotten that Audrey had left early that morning to pick up Isaac from the airport. He had just gotten back from France.

"Skylar? What is going on?" Isaac wondered.

"Just, hold on ok? Just hold on." Skylar bit her lip pacing in a tiny circle, once, twice, before a solution came to mind. "Ok, Audrey, Isaac, I need you to listen to me very carefully. I'm going to open the door now but I need you both to stand next to each other and don't move until I say it's ok."

Audrey hesitated, but her instincts won out. "Ok. We can do that." Skylar was acting strange. Something was obviously very wrong but Audrey trusted that Skylar was doing what she thought was best for all the people involved.

Skylar motioned to Derek and Scott to help her. She reached into her nightstand drawer and pulled out two small glass bottles, pushing one of them into Derek's hand before telling them what she needed them to do.

She and Derek stood shoulder to shoulder in front of the door, unscrewing their vials. She nodded to Scott who broke the salt barrier and ripped the door open. She and Derek lashed out, splashing the two people on the other side of the door. The sound of sizzling was heard and painful screeching.

Skylar immediately charged, Derek close behind her as he tucked a startled Audrey into the bedroom.

Skylar gripped Isaac's wrist and twisted his arm behind his back, the demon possessing him screaming as the holy water burned him. Before she could force him to his knees, the same inky black smoke erupted out of his mouth, taking refuge in the ceiling ducts once again.

Not wasting any time, Skylar tugged a dazed and confused Isaac into the bedroom, Derek slamming the door shut behind them as Scott repaired the salt border.

Audrey immediately went into frantic mother mode. "Is everyone alright? Isaac, are you ok? Oh my God! What happened to Liam?!"

Derek placed grounding hands on her shoulders. "Liam is going to be fine." He explained calmly. "It's a long story." He looked to Skylar, indicating that she needed to be the one to tell it since she actually knew what was going on.

"Yeah I'm going to be fine." A strained voice reassured. Liam was struggling to get himself into a seated position on Skylar's bed. His face was drawn and pale. He winced as he pulled at the still healing wound.

Scott was immediately by his side, gently gripping Liam's waist and maneuvering him into an upright position before sitting down next to him.

Liam sighed once he was able to lean against the headboard somewhat comfortably. He glanced around, looking surprised by Audrey and Isaac's arrival. "What did I miss?" He wondered.

"Why don't you sit down?" Skylar suggested, helping a dizzy Isaac to the edge of the bed.

Audrey followed their lead, plopping down next to him and holding back her questions.

"What just happened?" Isaac asked, clutching his head.

"I would like to know that as well." Liam seconded.

"You were possessed." Skylar said bluntly, tapping his chin so he would look up at her.

"Possessed?" Audrey echoed, looking at Isaac in barely-controlled panic. "By what?"

Skylar sighed. "A demon." She answered. She noticed Audrey's mouth opening to ask more questions so she cut her off. "He's fine. There isn't any lasting damage. He's just going to be dizzy for a minute." Skylar soothed.

Audrey nodded and paused for a moment before finally asking the question she needed answered the most. "How do you know so much about this Sky?"

Skylar turned away and began pacing as Stiles and Derek also gathered around.

"I've experienced this particular demon before." She said reluctantly. Half of her didn't want to talk about it because it was a very dark time in her life, but the other half needed to get this off her chest, and maybe if they knew, then maybe they could help.

Everyone was still looking at her expectantly.

She sighed, running a hand through her hair. "Ok." She conceded.

So, Skylar sat down in front of her friends, and she told them everything.


	4. Chapter 4

Dean's face stayed cemented in a scowl, his pedal almost to the floor. He sped around a corner, almost wrapping them around a tree.

"Whoa. Dean." Sam barked from the passenger seat, arms rigid where they were braced against the dashboard, trying to keep his body somewhat in place. "You need to slow down." He advised.

Dean scowled harder if that was even possible. "We need to get there as quickly as we can."

"Well, we'll never get there at all if we're dead." Sam reasoned. He saw the indecision flicker in his brother's eyes before he let off the gas just a bit.

Sam let out the breath he didn't know he'd been holding and allowed himself to settle comfortably back in his seat again. "Why is this job so important to you anyway?" He ventured cautiously.

Dean's eyes flicked over to him before going back to the road. He finally let his scowl drop as he sighed. "It was a bad one. I was on a call by myself."

Sam knew what that meant. It was when he and Dean had gone their separate ways, but he didn't say anything, just waited for Dean to continue. If he interrupted, his brother might shut down and not tell him anything at all.

"I was on the trail of a demon. I was supposed to meet up with the local hunter. But I screwed up. I followed some bad information. The damn thing had me on a wild goose chase while it went after a poor family." Dean's knuckles were white as his grip tightened on the steering wheel. He paused for several moments, not looking at Sam, not looking at anything really. He was remembering that night. Remembering the promise he made to a little girl.

Sam gulped. "What-what happened to the family?" He whispered. Any louder and he was afraid he would startle his brother into silence.

Dean's head shook almost imperceptibly. "The demon possessed the older brother. Called himself Salem." Dean let out a shaky breath before continuing. "He took the biggest knife they had and stabbed the mother six times. Almost killed the little sister but he started fighting for control. Just before he could force Salem out, he stabbed him straight through the heart. He was dead before he hit the ground."

Dean's voice had lowered to a whisper and Sam found himself leaning toward him with wide eyes.

"And the sister?" Sam asked, his voice sounding hoarse from his mouth being dropped open. "What happened to her?"

"She lived. I found her sitting on the kitchen floor, she was covered in blood." Dean rubbed a hand over his tired eyes. "She had seen the whole thing. She watched her brother kill her mom, try to kill her, and then kill himself. They ruled it as a murder-suicide. No one knew who the father was, so she was sent to live with her aunt and uncle. She was ten years old."

Sam sat back, stunned. "Dean, this isn't your fault." He said gently.

"Yes it is." Dean whispered.

"No, it-"

"Damnit Sam!" Dean exploded suddenly. "I should've been there! I was supposed to be there! I could've helped. Maybe they would be alive right now. Maybe that little girl wouldn't be left without her family."

"Or you could've died with them." Sam pointed out, keeping a calm quality to his tone. "And all the people you did save, would be gone."

"So what are you saying? That they don't matter?" Dean's voice still had a hard edge but he wasn't yelling anymore.

"No of course not. But Dean, you can't save them all."

Dean didn't say anything more.

"Did something happen to her? Is that why we're going to-" Sam paused to look at the address Dean had scribbled down. "Beacon Hills?"

Dean nodded. "I promised her that I would be there if anything happened. I owe her that much."

"Why? Just because it was the demon you were hunting?"

"No. I mean yes, but that's not the only reason." Dean sighed, running a hand through his hair, his jaw clenched. "Her mother was the hunter I was supposed to be meeting. I was supposed to be at that house."

"Dean-"

"Sam, just drop it, please." Dean whispered.

Sam wanted to keep talking, to reassure Dean that this wasn't his fault, but he didn't. Because his brother asked him to.

"So what happened to her?" Sam started, dreading what he was about to ask, but knowing he had to. "Is she dead?"

Surprisingly, Dean shook his head. "No, she's the one who called. A demon possessed one of her friends and almost made him stab himself. Sound familiar?"

"That means-"

"Yeah Sammy. Salem is back. And he's trying to finish what he started." Dean's eyes were stormy as the gas pedal hit the floor.


End file.
